It's strange. There is no object that would cast shadows... maybe a bug?

...btw. isn't there a wall between the camera and the rest of the room? I mean if there was a wall right in front of the camera, it wouldn't be normally visible because of the Z-limits settings, but maybe the ART renderer behaves differently and the wall is visible in the rendered image...

The faces normals are probably reversed. The ART raytracer does not render the backs of faces, because realistically you wouldn't since there's never a back of an infinitely small plane. If this is true, when you select faces, and you're looking from the outside of the model, they'll appear yellow. Normally you want this, but not for a room since you'll be on the inside of it. You want the normals to be facing inwards as long as you're inside the room. So select all the faces if this is true and go "Edit>Flip Normals" or press "shift + n"

Its abandoned because my mascot is a SKELATON!sorry were you expecting a puppy dog?lol.i have the first two floors and the camera is able to go to the top of the stairs as of now.i will texture,furnish and add more proper style lights.maybe even a chandelair(french for chandeleir,or so i guess?) with a local light source.all after i get the camera motions,and the whole house.cant render yet,i'm moving and this is the last computer*.im taking 30 minute interval turns with little sister.i cant even come near the computer when shes on .she watches sailor moon on here.Thats not entirely beside the point though because a movie render would slow down the comp,therefore throwing her on a tandrum.